Location: Hard Winter Wheat Genetics Research Unit
Title: Molecular markers for leaf rust resistance gene Lr42 in Wheat Authors
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 31, 2013
Publication Date: June 1, 2013
Citation: Liu, Z., Bai, G., Bowden, R.L. 2013. Molecular markers for leaf rust resistance gene Lr42 in Wheat. Crop Science. doi: 10.2135/cropsci2012.09.0532. Interpretive Summary: Wheat leaf rust is an important wheat foliar disease worldwide. Growing resistant cultivars is one of the most effective approaches for disease control. Lr42 is a gene from a wheat relative, Aegilops tauschii, and was transferred into a hard winter wheat ‘KS93U50’. In this study, we confirmed that Lr42 is on the short arm of chromosome 1D and located it between DNA markers Xwmc432 and Xgdm33. Lr42 was recessive when rust pathogen isolate PNMR was inoculated. The DNA markers for Lr42 should be useful for cloning of Lr42 and stacking Lr42 with other resistance genes in breeding.
Technical Abstract: Wheat leaf rust, caused by Puccinia triticina Eriks, is an important wheat foliar disease worldwide. Growing resistant cultivars is one of the most effective approaches for disease control. Leaf rust resistance gene Lr42 was identified from a wheat relative, Aegilops tauschii Coss., and has been transferred into hard winter wheat. A previous study identified two markers closely linked to the gene on the short arm of chromosome 1D (1DS) using a near isogenic population, but flanking markers for Lr42 were not found. In this study, a new mapping population was developed from a cross between leaf rust resistant parent ‘KS93U50’ (Lr42) and a susceptible parent ‘Morocco’. F2 plants were analyzed with all simple sequence repeat (SSR) markers available from 1DS and both F2 plants and F3 families were evaluated for seedling resistance to isolate PNMR, an avirulent rust isolate to Lr42. The F2 data showed that Lr42 was recessive when isolate PNMR was inoculated. Seven markers were linked to Lr42 on 1DS and markers Xwmc432 and Xgdm33 flanked the gene at 9.3 cM apart with Xwmc432 as the closest marker to Lr42. The results confirmed that Lr42 is on the distal end of chromosome 1DS. The flanking markers for Lr42 should be useful for map-based cloning and marker-assisted pyramiding of Lr42 with other resistance genes in breeding.